Cokin A Series Filters are recommended for lenses between 36 and 62mm in diameter with a focal length over 35mm. Cokin square filters fit into a holder and are attached to a lens via an adapter ring.
For Digital camera, or Film camera with B&W films. With a Digital camera, can be used in either color mode, or B&W mode. For Black&White mode, set the menu on “B&W” position and use it like a Film camera. In landscape photography and B&W mode, it lightens the nature and especially the greenery scenes (forests, fields...). It improves the depth-of-field and creates some unique grey tones.